1. Field of the Invention
The present invention relates generally to an apparatus for forming or working a thin layer onto a wafer surface and, in particular, to such an apparatus for depositing, etching and/or ashing of thin layers onto the wafer surface by generating plasma using electron cyclotron resonance equipment.
2. Description of the Related Art
Deposition of thin layers onto a wafer surface may be performed using various existing methods for various purposes during the manufacturing of precision equipments in this field, one of which known methods may be referred to, for example, as plasma chemical vapor deposition (CVD) process using electron cyclotron resonance equipment.
For example, referring to a silicon thin layer deposition using the plasma CVD process, silane gas is mixed with hydrogen gas to provide reaction gas and a high frequency electric power is then applied to an electrode facing the wafer surface in the reaction gas. Once the high frequency electric power is applied into the reaction gas, the reaction gas dissociates to form an amorphous silicon thin layer on the wafer surface.
In a similar manner, formation of a silicon oxide layer on a wafer surface may be achieved by applying the high frequency electric power to a mixture of silicon-based gas such as silane gas, and oxygen-based gas such as N2O, oxygen gas, etc. and then dissociating the mixture gas.
An apparatus for etching a thin layer formed on a wafer is disclosed, for example, in U.S. Pat. No. 5,888,414 issued to Collins et al., wherein a plasma reactor chamber uses an antenna driven by high frequency energy, such as radio frequency (RF) energy that is inductively coupled within the reactor dome and the antenna generates a high density, low energy plasma within the chamber for etching oxygen-containing layers.
A plasma ashing apparatus for removing a resist film from a wafer surface is disclosed in U.S. Pat. No. 5,228,052 to Kikuchi et al., which discloses a vacuum treatment chamber for receiving therein a substrate coated with the resist film, and two electrodes disposed in parallel to each other.
The above-mentioned wafer treatment apparatuses utilizing plasma are conventionally disposed within a processing room within which about 2.45 GHz frequency of microwave is radiated onto an object material to be processed, e.g., a semiconductor wafer or a liquid crystal display (LCD) substrate in a reduced-pressure environment by a vacuum pump, while the reaction gas is introduced into the processing room such that the microwave radiation effects plasmarization of the reaction gas. Therefore, a part of the reaction gas could be formed into active radicals and active ions, that subsequently react on the object material to be processed to effect depositing, etching or ashing of a thin film.
In the prior art, a conventional antenna has been utilized to provide the object material with radiation of the RF microwave energy within the processing room of conventional electron cyclotron resonance equipment. However, because this type of antenna equipped with existing electron cyclotron resonance equipment usually can not control the microwave radiation pattern of the electron cyclotron resonance equipment, the antenna will still have a problem in that uniformity of microwave energy is substantially not controllable by an operator.